Investments - Analysis of Cost or Amortized Cost, Gross Unrealized Gains and Losses and Fair Value for Investments (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale
Total	$ 14,050	$ 12,979
Gross unrealized gain	29	61
Gross unrealized loss	1,236	908
Fixed maturities, at fair value	12,843	12,132
Corporate
Debt Securities, Available-for-sale
Total	7,786	7,412
Gross unrealized gain	27	37
Gross unrealized loss	700	580
Fixed maturities, at fair value	7,113	6,869
States, municipalities and political subdivisions
Debt Securities, Available-for-sale
Total	4,911	4,901
Gross unrealized gain	2	24
Gross unrealized loss	489	303
Fixed maturities, at fair value	4,424	4,622
Government-sponsored enterprises
Debt Securities, Available-for-sale
Total	897	186
Gross unrealized gain	0	0
Gross unrealized loss	23	3
Fixed maturities, at fair value	874	183
United States government
Debt Securities, Available-for-sale
Total	223	196
Gross unrealized gain	0	0
Gross unrealized loss	6	5
Fixed maturities, at fair value	217	191
Commercial mortgage-backed
Debt Securities, Available-for-sale
Total	214	250
Gross unrealized gain	0	0
Gross unrealized loss	18	16
Fixed maturities, at fair value	196	234
Foreign government
Debt Securities, Available-for-sale
Total	19	34
Gross unrealized gain	0	0
Gross unrealized loss	0	1
Fixed maturities, at fair value	$ 19	$ 33